<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>11_3编程练习_蝴蝶结</title>
    <style>
        div {
            width: 0px;
            height: 0px;
            border: 100px solid transparent;
            margin: 20px;
        }

        .div1 {
            border-left-color: red;
            border-right-color: red;
        }

        .bd1 {
            border-radius: 80px;
            border-left-color: red;
        }

        .bd2 {
            position: relative;
            top: -220px;
            left: -20px;
            border-radius: 80px;
            border-right-color: red;
        }
    </style>
</head>

<body>
    <div class="div1"></div>
    <div class="box">
        <div class="bd1"></div>
        <div class="bd2"></div>

    </div>
</body>

</html>